Lyon Gardiner Tyler Jr. did not meet his paternal grandfather when he was growing up in Virginia in the 1930s. He never had the chance to walk through fields with his grandfather or hear his stories about an earlier time — tales about growing up when George Washington was president and of going to Monticello, where he listened as a family friend played the fiddle. The friend was Thomas Jefferson.

In later years, Dr. Tyler went on to become a Navy officer, a lawyer and a professor of history — and practically the living embodiment of almost the entire history of the nation.

Until his death on Sept. 26, Dr. Tyler had been one of two living grandsons of John Tyler, who was president of the United States from 1841 to 1845. Dr. Tyler was born 63 years after his grandfather died. He was 95 when he died at a hospital in Franklin, Tenn., of complications from Alzheimer’s disease, said his daughter, Susan Selina Tyler.

As hard as it may be to fathom, just three generations of the Tyler family connected the 18th century to the 21st. John Tyler, the future president, was born in 1790. His father, also named John Tyler, had been Jefferson’s college roommate at William & Mary and was a lifelong friend.

In 1840, John Tyler was the running mate — and the second half of the campaign slogan “Tippecanoe and Tyler Too” — of Whig Party presidential candidate William Henry Harrison. One month after taking office in 1841, Harrison died, and Tyler became the 10th president.

John Tyler, whose lineage is nothing if not complicated, was the father of 15 children, more than any other U.S. president. He and his first wife, Letitia Christian, who died in 1842, had eight children.

In 1844, he married Julia Gardiner, with whom he had seven more children. Their fifth child, born in 1853, was Lyon Gardiner Tyler Sr. The elder Lyon Tyler, who was president of William & Mary from 1888 to 1919 and was credited with saving the college from closing, had three children from his first marriage to Anne Baker Tucker. After her death, he married Sue Ruffin in 1923, when he was 70.

The first of their two sons, Lyon Gardiner Tyler Jr., was born Jan. 3, 1925, in Richmond. He grew up surrounded by Tyler relatives in Charles City County, Va., along the James River between Richmond and Williamsburg.

“I heard too much about presidents growing up,” he said years later in speeches about his heritage. He recalled meeting a woman “when I was probably 3 or 4 years old,” who asked if he was going to be president someday.

“And I said, ‘I’ll bite your head off.’ She said, ‘And what will you do with the bones?’ and I replied, ‘I’ll ’pit ’em out!”

He was 10 when his father died in 1935 and was 16 when he entered William & Mary. He interrupted his studies to serve as a Navy officer in the Pacific during World War II and remained in the Navy Reserve for many years, reaching the rank of commander.

After receiving his bachelor’s degree in 1947, he went to law school at the University of Virginia, graduating in 1949. He served one term as commonwealth’s attorney in Charles City County in the 1950s, defeating a cousin in the election for the post.

He later lived in Richmond, practicing law and becoming director of the Virginia Civil War Centennial Commission from 1959 to 1963. In that role, he gave lectures throughout the state and helped produce educational programs and war reenactments. In his late 30s, he decided to change course in life and attended graduate school at Duke University, from which he received a doctorate in history in 1967.

He taught at the University of Richmond for a year, then five years at the Virginia Military Institute, where he redesigned the campus museum. He was on the faculty of The Citadel in Charleston, S.C., for about 20 years until his retirement in the early 1990s.

American history was not just Dr. Tyler’s academic specialty but his birthright. He often gave talks about his grandfather, who sided with the Confederacy after failing to negotiate a compromise that was aimed at avoiding a civil war. John Tyler was 71 when he died in 1862.

In speaking about his grandfather, Dr. Tyler liked to quote from an 1832 letter John Tyler wrote to one of his sons: “Truth should always be uttered, no matter what the consequences. . . . When I am in company with a double-dealing man — one who has one language on his tongue and another in his heart — I am involuntarily made to avoid him as I would a poisonous reptile. Trust such a person with not even the slightest circumstance on earth; for he will deceive you.”

Dr. Tyler had lived in Tennessee since 2000. His wife of 43 years, the former Lucy Jane Pope, a radio and television journalist, died in 2001. Survivors include their daughter, Susan Selina Tyler of Franklin; and his 91-year-old brother, Harrison Ruffin Tyler, the last surviving grandchild of John Tyler, of Charles City County.

In 2018, Dr. Tyler made his final public appearance at a gathering in Washington of about 50 descendants of presidents. In his later years, he was said to bear a striking resemblance to his grandfather.